Recently there has been renewed interest in the use of hyperthermia (elevated temperatures in the range of 43-55 degrees C) as a treatment for cancer, particularly as an adjuvant to radiation therapy and chemotherapy. Two of the major problems in hyperthermia are the design of epuipment to heat deep-seated tumors and thermal dosimetry, i.e., adequate knowledge of the temperature distributions produced by the equipment. The major objective of this research is to develop computer-based software packages for calculating temperature distributions for hyperthermia applicators. Our long term objectives are: (1) to be able to evaluate and compare theoretically existing hyperthermia systems for their capability to deposit energy into the tumor volume and to produce desirable temperature distributions, (2) to propose and evaluate new types of systems that might come closer to meeting the desired specifications for a clinical system, and (3) to develop algorithms that can be used for patient treatment planning for hyperthemia. The specific aims include: (1) the development of numerical methods for calculating the three-dimensional power deposition patterns and temperature distributions for commonly used hyperthermia systems; (2) studies of the optimum system parameters for heating tumors at various sites within the body; (3) comparative studies of three-dimensional models of various hyperthermia systems; (4) the development of methods for automated entry of specific patient anatomical information from CT or other imaging modalities into the computer; and (5) the development of two-dimensional software packages compatible with existing workstations that can be easily transferred to other institutions.